The present invention relates to a method and apparatus for wrapping a load with packaging material.
Loads have been stretch wrapped with stretch wrap packaging material by dispensing the packaging material, securing a leading end of the packaging material to the load or a turntable clamp, and providing relative rotation between the load and a packaging material dispenser to cause the load to be enveloped by the packaging material. The relative rotation can be provided several different ways. Either the load can be rotated on a turntable, or the dispenser can be rotated around the stationary load. Stretch wrapping usually employs a web of stretch film as the packaging material.
Semi-automatic stretch wrapping machinery requires the operator to attach a leading end of the packaging material to the load. This is typically accomplished by forming a rope in the leading end of the film and then inserting this end between the layers of the load or tying the end of the packaging material to the edge of the supporting wood pallet or any suitable outcropping on the load. This attachment must be relatively strong since it provides the resistance to pulling the film from the film dispenser during the initiation of the relative rotation between the load and the film dispenser. The attachment or tying of the film makes film removal more difficult after the load has been shipped to its destination.
Automatic stretch wrapping machines typically use film clamps that grip the film web between two opposed surfaces and use electrical or pneumatic actuators to open and close the clamps. Such film clamps create a xe2x80x9ctentingxe2x80x9d effect during wrapping due to the distance between the clamp and the load during wrapping, resulting in wasted film and loosely wrapped loads. Such clamps are expensive and may require costly maintenance for the electrical and mechanical actuators.
In light of these drawbacks, there is a need for a method and apparatus for wrapping a load with packaging material that operates as effectively as those previously developed but which can be manufactured at a lower cost.
Accordingly, the present invention is directed to a method and apparatus for wrapping a load with packaging material which provides advantages and obviates a number of problems in earlier methods and apparatus for wrapping a load.
To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described, the invention includes an apparatus for wrapping the sides of a load with packaging material including a load support surface for supporting the load during wrapping, a dispenser for dispensing packaging material, means for providing relative rotation between the dispenser and the load to wrap packaging material around the sides of the load, a packaging material holder for selectively holding and releasing a leading end of packaging material, and a support arm moveable above the load support surface for moving the packaging material holder between a radially outward position distant from the sides of the load and a radially inward position near the sides of the load.
According to another aspect of the present invention, the invention includes an apparatus for wrapping the sides of a load with packaging material including a dispenser for dispensing packaging material, means for providing relative rotation between the dispenser and the load to wrap packaging material around the load, and a packaging material holder with at least one vacuum cup for selectively holding and releasing a leading end of the packaging material.
According to a further aspect of the present invention, the invention includes an apparatus for wrapping a load with packaging material including a load support surface for supporting the load during wrapping, a dispenser for dispensing packaging material, means for providing relative rotation between the dispenser and the load to wrap packaging material around the load, a packaging material holder for selectively engaging and releasing a leading end of the packaging material, and a support arm connected to the packaging material holder for moving the packaging material holder and leading end of the packaging material from a packaging material engaging position distant from the sides of the load to a wrapping position near the sides of the load to wrap the packaging material about the sides of the load and the packaging material holder.
According to another aspect of the present invention, the invention includes an apparatus for wrapping a load with packaging material including a load support surface for supporting the load during wrapping, a dispenser for dispensing packaging material, means for providing relative rotation between the dispenser and the load to wrap packaging material around the load, a packaging material holder for selectively engaging and releasing a leading end of the packaging material, and a support arm connected to the packaging material holder for holding the packaging material holder and leading end of the packaging material in a wrapping position near the sides of the load to wrap the packaging material about the sides of the load and the packaging material holder and for moving the packaging material holder away from the sides of the load to release the packaging material after wrapping.
According to yet a further aspect of the present invention, the invention includes an apparatus for retaining and positioning a free end of packaging material to a load to be wrapped with a rotary stretch wrapping apparatus, including an unopposed packaging material holder moveable between a first position and a second position, a support arm for moving the packaging material holder between a position distant from the load to be wrapped and a position near the load to be wrapped, and a support frame for the support arm and configured to be mounted on or adjacent to a load support surface of a rotary stretch wrapping apparatus.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objects and other advantages of the invention will be realized and attained by the method and apparatus particularly pointed out in the written description and claims as well as the appended drawings.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention, and together with the description serve to explain the principles of the invention.